OALib Journal期刊

ISSN: 2333-9721




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匹配条件: “<br>曹宇” ,找到相关结果约274032条。
Analysis of landscape change drivers in the Ejina natural oasis

CAO Yu,<br>
生态学报 , 2004,
Abstract: The Ejina natural oasis landscape lies in the lower reaches of the Heihe river basin in the arid inland regions of northwestern China. With decreasing water resources from the upper reaches of the Heihe river basin, many urgent ecological and environmental issues in the Ejina natural oasis have become more pressing in recent years. Using remote sensing techniques and GIS, based on Landsat Thematic Mapper data in 1987 and 1994 and Landsat Enhanced Thematic Mapper Plus data in 2001, the changing patterns of the Ejina natural oasis landscape showed that: (1) During the past 15 years, the water area and main oasis area sharply decreased. The oasis desertification process is more serious at present than before. (2) The most intense conversion among different landscape types was occurring in the transitional zone between oasis landscapes and desert landscapes. (3) As results of the Ejina natural oasis landscape change, the landscape patch complexity and heterogeneity were significantly reduced. Moreover, the landscape texture became increasing coarse and the landscape diversity and stability were decreased. Based on the general characteristics of the Ejina natural oasis landscape during the past decade, some key driving factors, including climate change indicators, hydrological indicators and human activities indicators, were analyzed. The climate change indicators consisted of evaporation degree, wetness coefficient and dryness degree, which were calculated from the meteorologic data of precipitation, air temperature, evaporation and humidity from 1957 to 2001. The hydrological indicators were the annual change of surface water quantity from 1947 to 2001, the spatio-temporal change of groundwater level between 1980s and 2000s, and the change of groundwater quality in recent years. The human activities indicators were changes in total population, livestock quantity and farmland area in the past 50 years. Results show that: (1) Increased evaporation degree, decreased wetness coefficient and enhanced dryness degree in the past decade, especially in recent years, all accelerated the desertification of the Ejina natural oasis landscape; (2) Significantly reduced surface water quantity from the upper reaches of the Heihe river basin, which simultaneously led to descending groundwater level, ascending groundwater mineralization degree and soil saltness content, and badly deteriorating water quality, was the key driver for the degradation of the Ejina natural oasis landscape; and (3) Increased intensity of human activities induced by rising population and livestock in recent decades, overgrazing livestock in the fragile natural oasis regions, and frequently reclaiming and abandoning farmland owing to unbalanced distribution of limited water resources were also important driving factors for the Ejina natural oasis landscape degradation in past decades. Furthermore, owing to the ecological fragilities and the difficulties of ecological restoration for the natur
cquisition of Tongue Diagnosis: An Ontology-based Approach

CAO Yu-feng,CAO Cun-gen,<br>,存根
计算机应用研究 , 2006,
Abstract: Tongue diagnosis is a profound and special part of the whole traditional Chinese medicine, and knowledge of tongue diagnosis is the basis for many computer applications such as automated diagnosis and therapy, medical instruction and training, and natural language processing. This paper introduces a domain-specific ontology of tongue diagnosis, it has been built 9 categories about TCM tongue diagnosis and other relevant categories.
Landscape health assessment on Ejin natural oasis

CAO Yu,OUYANG Hua,XIAO Duning,<br>,欧阳华,肖笃宁
应用生态学报 , 2005,
Abstract: Landscape scale ecosystem health research could not only provide a basis for integrating natural ecological processes and social economic values,but also provide an appreciated temporal and spatial scale in dealing with the issues of resources and environment.The Ejin natural oasis landscape is at the lower reach of Heihe river basin in the arid inland regions of northwestern China.Owing to the lack of sufficient water resource from the upper reaches of Heihe River,a series of ecological and environmental problems are getting more serious in the oasis in recent years.Based on the past decade landscape change of the Ejin natural oasis,this paper developed a landscape health indicators system including landscape change indicators,bio-physical indicators,eco-environmental indicators and social-economic indicators,and established the criteria and weightiness for assessment indicators.The landscape health index (LHI) was finally figured out as 0.3042 by using fuzzy comprehensive evaluation method,which showed that the health condition of Ejin natural oasis landscape was ranked to "severely ill level" in the landscape health assessment criteria system.The landscape health of Ejin natural oasis landscape today is much worse than in the past years,with a badly unsustainable developing trend.
Limitations of landscape pattern analysis based on landscape indices: A case study of Lizejian wetland in Yilan of Taiwan Province, China

LIN Meng-lung,CAO Yu,WANG Shin,<br>林孟龙,,王鑫
应用生态学报 , 2008,
Abstract: In this paper, the Lizejian wetland landscape patterns in northeastern Taiwan of China were established by landscape indices and aerial photo interpretation, and a parallel analysis was made on them. The results showed that landscape indices could only indicate the landscape geometric characteristics of the wetland at patch and landscape levels, but could not present its spatial and functional characteristics observed from aerial photos. Combining aerial photo interpretation with landscape indices could be helpful to the holistic understanding of Lizejian wetland' s landscape structure and function, and improve the landscape pattern analysis. The new method for assessing landscape structure from a holistic point of view would play an important role in future landscape ecology research.
Research on Capacity of Multicarrier CDMA

Wang Peng,Zhao Yu,Cao Da-zhong,<br>王 鹏,,达仲
电子与信息学报 , 2007,
Abstract: Theorelical and mathematical analyses of multicarrier CDMA capacity planning are proposed and the expressions of capacity for multicarrier CDMA are derived both in uplink and downlink. Through extremum of a multivariate function (by Lagrange multipliers), the maximum capacity of multicarrier CDMA is achieved from the viewpoint of voice and data, respectively. Simultaneously, the important conclusions are got for multicarrier CDMA: when BS maximum transmit power is average distributed for all subcarriers, the maximum of capacity is achieved. Simulation results show that capacity of all kinds of service will decrease rapidly as average path loss increase. The essence is opened out between capacity and coverage: capacity and coverage restrict each other, decreasing in capacity means extend in coverage, and vice versa. When transmit power is in higher level, increasing power is not an effective way to improve capacity. From comparison between GSM, WCDMA and multicarrier CDMA, the conclusion are achieved that the spectrum efficiency of multicarrier CDMA is 1.7 times that of WCDMA, and 2.7 times that of GSM in downlink; and 2.1 time that of WCDMA, and 2.4 times that of GSM in uplink.
The Primary Study on a Method of Nonlinear Dynamic System Prediction

Zhang Wangcheng,Wang Yu,Cao Jie,<br>张万诚,,
大气科学 , 1997,
Abstract: In this paper, a method of nonlinear dynamic system prediction is given. The catastrophe of predictor and the unbalance of time dependent parameters are considered in thes method. The results of the numerical experiments have shown that the prediction accuracy of using this nonlinear dynamic prediction system is more effective them that of using the gereral recursive estimating method.

Cao Yujing,Jiang Guangtai,Zeng Guoqing,<br>,蒋广泰
动物学研究 , 1997,
Abstract: 本文采用子宫内注射和胚胎与子宫上皮细胞在体外共培养的方法,研究几种蛋白酶抑制对小鼠胚胎着床的影响。实验结果显示,蛋白酶抑制剂STI,EACA和NPGB均能显著抑制胚泡在子宫内着床;STI和EACA能有效地抑制胚泡在子宫上皮细胞单层上的扩展,而NPGB对胚泡在子宫上皮细胞单层上的粘附和扩展均有显著的抑制作用。
Local self-similarity based image super-resolution reconstruction algorithm

Yang Yuxiang,Cao Yang,Wang Zengfu,<br>杨,,汪增福
中国图象图形学报 , 2011,
Abstract: Image super-resolution refers to reconstruction of a high resolution image from one or a set of blurred low resolution images. This paper only pays attention to the kind of reconstruction from one blurred low resolution image. Many methods have been developed for this kind of reconstruction, most of which are MAP methods and interpolation methods. This paper proposed a new interpolation method. The proposed method used the quad tree segmentation to partition the low resolution image, the edge-directed interpolation to each segmented band of the low resolution image, and a wavelet projection to optimize the high resolution image obrained from the local interpolation. The experiment used the peak signal to noise ratio (PSNR) to compare the reconstructed image with the original image. And the results showed that the PSNR and visual effect of the high resolution image reconstructed with the proposed method were very good.

CAO Chongde,LU Xiaoyu,WEI Bingbo,<br>崇德,鲁晓,魏炳波
金属学报 , 1998,
Abstract: 采用熔融玻璃净化法使大体积Co85Cu15亚包晶合金的最大过冷度达到351K,实验测得其超过冷临界过冷度为379K,随着过冷度的增大,显微组织由树枝晶转变为等轴晶,并显著细化;溶质截留效应增强,显微偏析程度减小,Co的同素异构转变受到抑制,凝固组织中Co主要是亚稳的过饱和α-Co固溶体,ε-Co含量极少。
Development of Web Experimenting System(WES) and Multimedia Courseware Based on Internet

LI Yan,CAO Yan,JIANG Ping- yu,<br>黎岩,,江平
计算机应用研究 , 2004,
Abstract: Based on Web technology,ASP,ADO,Database and so on are utilized to build up the WES and multimedia courseware.According to the experimental requirements,the system is divided into two main parts:teacher's management and student's experiment.Its functions include multimedia teaching instances,simulation experiments,experimental report generation based on database,report check,etc.Finally,a practical example is provided to illustrate the functions and methods of the WES.

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